Two traditional equating schemes and seven item response theory equating schemes were compared. Data used came from the 1978 equating project of the Iowa Tests of Educational Development. The study entailed both the equating of forms of similar difficulty and the equating of levels of differing difficulty. (Arthor/RL)

This paper describes and illustrates a method for equating examinations with multiple facets (i.e., items, examinees, judges, tasks, and rating scales). The data are from the practical section of two histotechnology certification examinations. The first practical examination involved 210 examinees, 14 judges, 15 slides, 3 tasks, and 2 rating…

The equating of scores on alternate forms of different achievement tests through the use of the three-parameter latent trait model, item-response theory (IRT) equating, was compared with the results of score equatings based on conventional linear and curvilinear equating models. Ten equatings were completed for pairs of alternate forms of the…

The purposes of this paper are five-fold to discuss: (1) when item response theory (IRT) equating methods should provide better results than traditional methods; (2) which IRT model, the three-parameter logistic or the one-parameter logistic (Rasch), is the most reasonable to use; (3) what unique contributions IRT methods can offer the equating…

Two tests were created from a standardized reading achievement test and vertically equated using a sample of third and fourth grade students. Based on differences in ability estimates for the same student, the Rasch model did not provide a satisfactory means of vertical equating. (Author/CM)

Levine's equations for random groups and unequally reliable tests can be used to equate two tests through performance on an anchor test. Levine's assumption of a parallelism requirement is not necessary; it is sufficient to assume only that the tests are congeneric, an assumption implicit in linear test equating. (SLD)

To explore the appropriateness of the Rasch model for the vertical equating of a multi-level, multi-form achievement test series, both the Rasch model and the traditional Thurstone procedures were applied to the Listening Comprehension subtest scores of the Stanford Achievement Test. Two adjacent levels of these tests were administered in 1981 to…

Procedures used to compare the results from item response theory as well as more traditional equating methods were described and critically analyzed. The implications of the comparison of equipercentile, linear, one-parameter (Rasch), and three-parameter methods for equating twelve forms of each of the five tests of General Educational Development…

Seven papers on technical and practical issues in equating are presented. Problems related to the use of conventional and item response theory equating methods, using pre- and post-smoothing to increase equipercentile equating's precision, and linear equating models for common-item nonequivalent-population design are discussed. (SLD)

Item response theory equating invariance was examined by simulating vertical equating of two sets of examinee ability data comparing Rasch, three-parameter, and equipercentile equating methods. All three were reasonably invariant, suggesting that multidimensionality is likely to be the cause of lack of invariance found in real data sets. (SLD)

Item response theory (IRT) is having a major impact on the field of testing. This special issue presents an introduction and seven papers concerning developments in IRT applications. Some important IRT research being conducted outside the United States is highlighted. (SLD)

The purpose of this study was to empirically examine the relationship between violations of the assumption of unidimensionality, as assessed by the factor analysis of item parcel data, and the quality of item response theory (IRT) true-score equating, as measured by score scale stability. The verbal section of the Scholastic Aptitude Test (SAT)…

A formula is derived for the asymptotic standard error of a true-score equating by item response theory (IRT). The equating method is applicable when the two tests to be equated are administered to different groups along with an "anchor test." Numerical standard errors are shown for an actual equating 1) comparing the standard errors of…

The purpose of this study was to determine the extent to which item parameters estimated on pretest data from the verbal section of the Scholastic Aptitude Test (SAT) can be used for equating purposes in a situation where intact final form SAT testing data have normally been used. Items appearing in two final SAT-verbal forms were calibrated…

This study investigated the development and application of two widely used methods of vertical equating: Rasch and Equipercentile. The assumptions underlying both techniques are discussed. Procedures for utilization of the Rasch method are illustrated. The study was conducted to determine whether, based upon Rasch vertical equating, a local school…